[peteeng]

Hi All - The 600W DC spindle has been running 360hrs. I expect the two bumps in its life have affected its overall life. It has an 8mm dia shaft so is a bit small really. But been a good experiment.

In Scoot-S1 I had a Makita 700W RT0700 trimmer and it wore the brushes out in 660hrs. Put new brushes in and it seemed to run like new, I gave that Makita hell. Then I sold it for nearly what I paid for it when I went to a new DC spindle on Scoot-S1. Does anyone know the expected life of typical Chinese AC spindles? Peter

[mactec54]

Hi All - Decided to catch up on the bee engraving and got it done. The edges were a bit fuzzier then normal and I noticed a slight kick around one corner but it got done. I then set up a small piece from the bee cut up to turn into a coaster and the spindle sort of buzzed then the tool feel off. Classic beach striations marks with an ultimate fracture zone. So I'll have to rig my trimmer up to Scoot until a 1.5kW arrives.... damn and an order just left Shanghai... I'll wait for Frankies ballscrews to add to. I didn't order the screws as the drawing for the aluminium motor mounts was incomplete so will measure them up and and then order ballscrews to suit length. Plus the new spindle... I don't have a clamp for the trimmer so will need to make one.... Tomorrow on Brevis... Peter

Thats a big cutter to use with that spindle, they are just an electric motor with an ER chuck on them, so not really designed to be a spindle, to have a side loading with a big cutter, it has lasted well for what it is, you may be able to make a new shaft for it, and good to go again, the shaft may be just pressed into the rotor so may be an easy fix.

[mactec54]

Hi All - The 600W DC spindle has been running 360hrs. I expect the two bumps in its life have affected its overall life. It has an 8mm dia shaft so is a bit small really. But been a good experiment.

In Scoot-S1 I had a Makita 700W RT0700 trimmer and it wore the brushes out in 660hrs. Put new brushes in and it seemed to run like new, I gave that Makita hell. Then I sold it for nearly what I paid for it when I went to a new DC spindle on Scoot-S1. Does anyone know the expected life of typical Chinese AC spindles? Peter

The AC VFD Drive Spindles don't have this problem, and those that have them setup correct, have been using them for years, Bearings can be replaced which is what normally fails

[peteeng]

Hi All & Sundry - Todays work - I went to the Menshed where my Brevis is and used it to pocket the clamp hole for the Ozito. All went well. I decided to make the clamp out of some PET/epoxy board I made over 15 years ago. It was a good thickness for the clamp and has been sitting their patiently for a purpose. I used to make tooling board for a company from PET geotextile cloth and epoxy. They used it for NC program proving. So I bored the hole and will cut the clamp profile on my saw later today.

I also went to the fastener shop and got some half nuts and coupling nuts for Matts build. Now the Z axis is ready to go... I ordered the saddle yesterday so its all go. I'll order the new spindle this afternoon as well. I also have some 0.3mm shim washers coming for the tramming. Now once Scoot-S2 has the ozito running i can get back to sorting the inverter... Peter

[peteeng]

Evening All - Ozi Tool to the rescue! Now I have a composite, damp router mount! Haven't used it in anger yet. Will regroup the ToDo list and see what's to do. Does need a high support could vibrate a little. Peter

[luke peter]

How stiff is the composite board you made Peter?

[peteeng]

Hi Luke - Its PETE Plastic and epoxy so nothing like a metal. The PETE is around 3000MPa and the epoxy is 3500MPa and its about 50/50 by volume so around 3250MPa will be about it... maybe 3000-3500MPa It feels like a chunk of acetal... Peter

[luke peter]

That makes sense for what you made it for - does it damp well?

Acetal is really nice polymer, I made a bunch of roll splitting wedges for my production counterparts to use to separate pulp rolls that were intertwined on the rewinder, some out of UHMWPE and some out of acetal, and I was very surprised how much denser it was than the UHMW.

[peteeng]

Hi Luke - I'll call the composite Tetrium-P when you tap it it rings like acetal (POM) does. I presume its very damp compared to metals as its a polymer plus its a mixed polymer. I make it by cutting up PET geotextile cloth, stacking it in a vacuum bag (or mould) then infusing it with resin. I have made 75mm thick slabs 400x400mm but I think its scalable to nearly any size. I used to make near nett chunks of it for a company to run proving NC programs before simulation of toolpaths became cheap and available. Maybe I'll do a glass or CF one for Frankie. I used to get a resin from SA that I really liked for this sort of thing. Its a polyester tooling resin and its the thinnest resin I have ever come across much thinner then the thinnest epoxy. Its a duplex resin. It has PET in it to compensate for the polyester shrinkage. It cures white. But they now bring it in promoted & mixed with a filler and that does not suit me. Peter

[peteeng]

Hi Luke or others - If your thinking of mineral casting this would be the resin to choose vs epoxy. Unless your familiar with epoxy... But I would get it unfilled if possible.

https://pdf.directindustry.com/pdf/r...55-706373.html No need for post curing it does get very hot though. Peter

https://www.ncsresins.com/contact-us/

edit - POLYLITE® PROFILE POLESTER RESIN TOOLING MANUAL - Reichhold - PDF Catalogs | Technical Documentation | Brochure (directindustry.com) this is the one unpromoted, unthixotroped. So you can promote it yourself on site so the resin never goes off and you can control the gel time accurately. Unthixed means its extremely thin so you could dry stack the mould and then pour in the resin and it would wet out nicely. Just keep adding resin until the mould or stack fills. ie no porosity from mixing resin and filler all at once. It is a fast curing resin compared to epoxy so you need to adjust promotion and catalyst way down for this exercise... do test mixes... Peter

https://www.facebook.com/ScootCNC/vi...68682127776789

[luke peter]

Thanks for the info Peter.

I have no plans to do any significant casting for the near future, but its a branch of material science I have next to no experience with (almost all my work related material is super duplex stainless or high grade austenitic), and I think that more is better when considering options. There are many cases where chemically inert plastics would probably suit better than the stainless in my applications, especially as coatings.

[AdeaLeka]

10 mm

[peteeng]

Evening All - Today I tried to catch up from the epoxy stuff up. I found a nice piece of wood and designed the board. I started milling it and hit a small problem. The Z didn't go down far enough. I didn't check the Z travel when I made the Ozito adaptor!! So I looked around and couldn't find a piece of aluminium or steel to do the job. Its Friday afternoon so too late to go around to some of the usual's in town. So I grabbed some 16mm very high tech laminate (well in the 2nd world war it was high tech) with special phenolic coating to boot and made an extension. (Formply for those who know) then got back into the job. So now it needs to be finished and I can get into Frankies Gantry... The router is noisy but does a good job. I think I must have figured something was going on with the DC spindle because I realised I was babying it a bit before it broke. I ramped up the Ozito and it was quite happy at 2000mm/min and 5mm doc... but the camphor is a bit soft... So onward to the next project... Peter

[peteeng]

Hi All and Sundry - I pocketed the hand holes which pitch matched my grid pitch, then clamped thru the hand holes to do the profile. Peter

[JohnatanF]

Did you design the table yourself?

[peteeng]

Hi Luke - So your next machine will be made from SAF2507? Peter

[luke peter]

Hi Luke - So your next machine will be made from SAF2507? Peter

Only a little 2507 in my plant, but lots of 2205, 254SMO and 904l I cried a little when I first started here, when I saw how much good stainless gets sold off to the scrap dealer at the equivelant of 0.4AUD a kg...

[peteeng]

Hi Luke - I've used a lot of 2205 for yacht parts. Plus a lot of 17-4PH on yachts. Nice to work with... So you could make a machine from scrap... Peter

[peteeng]

Evening all and Sundry - Scoots job today was to make 2 electrical panels for a friend. But only got one done. The collet in the Ozito allows the tool to slip down I've found. Caught it twice, broke a 2mm tool once.... what a pain. I haven't done any perspex before so took it slow. The engraving tool was also a bit of a worry. It was Dia6mm in the 1/4" collet but it didn't move. Much lower loads I expect. So probably finish the other one Saturday. Wanted to get 3 other things done today but all my time seemed to disappear... want my 1.5kW spindle asap! The Ozito is so noisy. Frankie's parts arrived today so need to get that rolling....Peter

[JohnatanF]

10 mm

right!